Extracorporeal shock wave therapy (ESWT) is non-surgical, noninvasive treatment of medical conditions using acoustic shock waves. First use of shockwave therapy in the early 1980's was utilized to fragment kidney stones termed shockwave lithotripsy. Continued development of shockwave treatment showed the possibility of stimulating bone formation, angiogenesis, as well as other orthopedic indications.
A shock wave is a type of acoustic energy resulting from phenomena, such as an explosion or lightning, that create a sudden intense change in pressure. The intense changes in pressure produce strong waves of energy that can travel through any elastic medium such as air, water, human soft tissue, or certain solid substances such as bone.
Acoustic shock waves for ESWT are primarily generated by three different methods, electrohydraulic (also referred to as spark gap), electromagnetic (also referred to as EMSE), and piezoelectric. Each method needs and apparatus to focus the generated shockwave so as to provide a focal point and/or focal zone for the treatment area. In the focal zone, the shock waves produce much higher pressure impulses as compared with the zone outside of the focal zone. Mechanical focusing for each of these methods is generally realized with an appropriate arrangement of surfaces reflecting the wave toward the desired focal point and/or an appropriate arrangement of the generating devices.
Spark gap systems incorporate an electrode (spark plug) to initiate a shock wave and ellipsoid to focus it. EMSE systems utilize an electromagnetic coil and an opposing metal membrane. Piezoelectric systems form acoustical waves by mounting piezoelectric crystals to a spherical surface to provide focus. Of the three systems, the spark gap system is generally preferred in the art for ESWT as it utilizes more of the generated shockwave energy to the treatment target site.
In spark gap systems, high energy shock waves are generated when electricity is applied to an electrode positioned in an ellipsoid immersed in treated water. When the electrical charge is fired, a small amount of water is vaporized at the tip of the electrode and a shock wave is produced. The shock wave ricochets from the side of an ellipsoid and converges at a focal point, which may then be transferred to the area to be treated.
In electromagnetic systems an electrical impulse is circulated in a coil. The coil produces an electromagnetic field that expels a metallic membrane to produce the mechanical impulse.
In piezoelectric systems a ceramic material with piezoelectric characteristics is subjected to an electrical impulse. The electric impulse modifies the dimension of the ceramic material to generate the desired mechanical impulse. A focal point is attained by covering a concave spherical surface with piezoelectric ceramics converging at the center of the sphere.
The method of focusing the generated shockwave has been greatly described in the art for example in U.S. Pat. Nos. 5,174,280 and 5,058,569, U.S. Pat. No. 5,033,456, EP1591070 all of which are incorporated herein by reference as if fully set forth.
Medical use of shockwave therapy provides noninvasive means for treating a variety of anomalies such as kidney stones, chronic orthopedic inflammation healing, bone healing, wound healing, osteogenesis, revascularization, angiogenesis are known in the art. ESWT has also been described in attempts to treatment of Peyronie's disease.
Peyronie's disease consisting of penile deformity and angulation has been treated with shockwave therapy since early 80's. Such shockwave treatment attempts to soften plaques formed in the tunica abluginea causing painful erection and penile deformation, as well as improving its elastic nature. Recently reported Peyronie's treatment regimen includes five (5) sessions where each session provides 3000 shockwave with emission frequency of 120 waves/min, energy intensity of 0.11 to 0.17 mJ/mm^2, International Journal of Impotence Research (2004) 16, 448-451; similar treatment regiments were also reported in J Endourol. 2005 January-February, vol. 19(1):11-4. The ESWT for Peyronie's is primarily set to soften the plaque causing penile deformation and angulation, as well as increasing the vascularity of the area of the plaque.
Erectile dysfunction (referred to herein as ED) can be caused by physiologic, neurogenic, vasculogenic, hormonal, or psychological factors. The term “erectile dysfunction”, as used herein, refers to the inability or impaired ability of a male individual to experience a penile erection.
Normal erectile function requires adequate penile arterial inflow, sufficient corpora cavernosal expansion, and competent venous sinusoidal outflow occlusion. Severe malfunction of any one of these components, or a cumulative failure of multiple components, will result in erectile failure leading to erectile dysfunction. Improved treatment of erectile dysfunction has made it necessary to access erectile physiology more accurately in order to determine which vascular component is dysfunctional and to distinguish whether a patient suffers from a physiologic, neurogenic, vasculogenic, hormonal, or psychologic etiology for his erectile dysfunction.
The penis is divided into four hydraulic chambers: two corpora cavernosa, a corpus spongiosum, and a glans. Although all contain sponge-like sinusoidal tissue, only the corpora cavernosal sinusoids contain the venous sinusoidal occlusion mechanism. By permitting blood to flow into but not out of the corpus cavernosum, the venous sinusoidal mechanism can transform the corpus cavernosum from an open to a closed chamber capable of trapping blood and thus producing rigid erections.
Under normal circumstances, each corpus cavernosum is supplied by its own cavernosal artery. Cavernosal artery flow and pressure determine the competence of the erectile process. The dorsal and bulbar arteries supply blood to the skin of the penis, glans, and corpus spongiosum, playing only a minor role in the erectile process.
The erectile cycle can be divided into four phases: initiation, generation, maintenance, and detumescence. The earliest phase of erection, initiation, occurs when a neurochemical stimulus causes a rapid inflow of arterial blood into the corpora. The sinusoids become engorged. Generation occurs when the venous outflow mechanism closes. Blood is then stored in the corpora cavernosal bodies. The penis expands until full rigidity is achieved. Maintenance occurs when the corporal bodies are fully expanded and the arterial inflow and venous outflow are in an equilibrium state such that full penile expansion and pressure are maintained. Detumescence is the process whereby full erection is lost by either a decrease in arterial inflow or an increase in venous sinusoidal outflow.
Urologists and practitioners have devised a number of therapies for treating erectile dysfunction. These therapies include psychological, surgical, pharmacological, ultrasound and electrical therapies.
Method and devices for electrically stimulating a penile erection are disclosed in U.S. Pat. No. 4,585,005 to Lue et al; U.S. Pat. No. 5,571,118 to Boutos and U.S. Pat. No. 4,542,753 respectively.
Pharmacological therapies for erectile dysfunction include the injection of drugs into the penis, urethra as disclosed in U.S. Pat. No. 5,236,904 to Gerstengerg et al. and U.S. Pat. No. 4,127,118 to Latorre. More recently oral drugs, such as VIAGRA®, have been used to treat ad hoc episodes of ED have been widely used for the maintenance of an erection.
U.S. Pat. No. 6,469,012 to Ellis et al assigned to Pfizer teaches an orally administered drug comprising pyrazolopyrimidinones sold under the brand name VIAGRA® teaches the selective enzymatic inhibition of potent inhibitors of cyclic guanosine 3′,5′-monophosphate phosphodiesterases (cGMP PDEs) in contrast to their inhibition of cyclic adenosine 3′,5′-monophosphate phosphodiesterases (cAMP PDEs) that leads to elevated cGMP levels in the corpus cavernosum that then brings about the relaxation of the corpus cavernosum tissue and consequently mediating penile erection
PCT Publication WO9912514 to Redano teaches an apparatus and method for treating erectile dysfunction using ultrasound penile treatment by stimulating hemodynamic activity within a penis by increasing hemodynamic flow to the penis with the use of ultrasound energy source to the outer surface of a penis. Redano also teaches an ultrasonograph measuring one or more hemodynamic parameters within the penis, for example blood flow velocity, blood pressure, and/or blood temperature that may be used to determine treatment or cause for erectile dysfunction.
A further treatment for Erectile Dysfunction known in the art comprises a vacuum pump or a Vacuum Constricting Devices (VCD) comprising a housing for the penis coupled to a pump and a constricting ring. The housing is placed over the penis and coupled to an air pump to create a vacuum within the housing over the penis therein urging blood into the penis to mediate an erection while a constricting ring is placed over the base of the penis to constrict blood flow out of the penis to maintain the erection. While the various VCD solutions do bring about an erection they do not treat the underlying causes of Erectile Dysfunction therefore providing an ad hoc solution to ED.
Other treatments of ED know in the art includes invasive and/or long treatments such as intraurethral suppositories, vascular surgery in case of arterial insufficiency, penile implants, hormone therapy and psychosexual treatment.